An electronically steerable array antenna is an antenna system that includes an array of individual antenna elements that transmit a same radio frequency (RF) signal with different relative phases. Destructive and constructive interference of these RF signals may form a directional beam. By adjusting the phase relationship between the signals transmitted by these respective antenna elements, the direction of the beam may be adjusted using electronically steerable array beam steering methods known in the art. Such beamforming and beam steering methods may be applied, for example, to one-dimensional electronically steerable array antennas that have a single line of antenna elements, in which case the beam may be steered in a single direction. These techniques may also be applied to two-dimensional antenna arrays in which a beam may be electronically steered in two dimensions to adjust both an azimuth and elevation of the beam.
A common application that uses electronically steerable array beam steering techniques is that of a radar system. By using an electronically steerable array antenna, the direction of a transmitted and received radar signal may be adjusted using electronic beam steering techniques instead of mechanically moving an antenna. A further application of electronically steerable arrays is in cellular communications. By using a steerable beam, spatial multiplexing increases network capacity by multiplying the spectral efficiency.